This project continues to focus on the development of an effective post- exposure treatment of rabies in humans and efficacy testing of genetically engineered subunit vaccines. Sensitive molecular biological techniques will be employed to study the pathogenesis of rabies and the effector mechanisms involved in the immune defense of rabies encephalitis In particular we will: 1. Effectively define a more rational post-exposure treatment protocol for humans against rabies. We will investigate the efficacy of a "cocktail" of murine anti-rabies monoclonal antibodies (MAbs), alone and in various combinations with rabies vaccine, in the induction of protective immunity and the effect upon the induction of T-helper and cytotoxic T cell responses in relevant animals models. Using recombinant DNA techniques, the mouse MAbs genes will be "humanized and similarly analyzed. Additional human rabies-specific virus-neutralizing MAbs will be generated, characterized and analyzed for post-exposure efficacy in laboratory animals. 2. Resolve the three-dimensional structure of the rabies virus glycoprotein by x-ray crystallography and determine the topographical localization of operationally-defined viral epitopes. 3. Determine the mechanisms involved in rabies virus pathogenesis using in vivo models. The early events of rabies viruses infection prior to CNS infection and its progress to the CNS will be studied using a polymerase chain reaction for the amplification of rabies-specific A+RNAs. 4. Investigate the immunopathology of rabies virus infection of the central nervous system (CNS). Purified goat anti-idiotypic antibodies to mouse anti-rabies immunoglobulins will be used to identify rabies virus- specific B cells in the CNS of rabies-inoculated animals. 5. Determine the immunological consequence of tolerance to rabies glycoprotein in rabies virus pathogenesis and prophylaxis. Transgenic mice will be generated using and SV40 vector for the incorporation of the rabies virus glycoprotein gene. These tolerant mice will be vaccinated and challenged with rabies virus to determine the role of virus- neutralizing antibody in rabies prophylaxis. 6. Characterize and develop genetically engineered glycoprotein and nucleoprotein subunit vaccines. The safety and efficacy of a well-tested vaccinia-rabies glycoprotein recombinant virus vaccine for wildlife rabies control will be evaluated in the field. The primary immune response and induction of protective immunity of engineered rabies N and G proteins alone will be analyzed in pre- and post-exposure animal models. 7. Identify and characterize strain-specific epitopes of street rabies viral antigens. Murine MAbs to natural virus isolates will be produced in order to refine our understanding of rabies epidemiology and diagnose the potential sources of exposure of humans and domestic animals lacking a firm history of animal bite.